Biology 0610/52 October/November 2023: question paper and mark scheme
Cambridge IGCSE Biology (0610), Paper 5 Practical Test, October/November 2023. Read both free below, or download them. Done the paper? Get it marked by AI against this mark scheme.
You are going to investigate the effect of temperature on the activity of amylase.
Amylase is an enzyme that catalyses the breakdown of starch to form reducing sugars.
Read all the instructions but DO NOT DO THEM until you have drawn a table for your results in the space provided in 1(a)(i).
You should use the safety equipment provided while you are doing the practical work.
Step 1 Use the pen to draw a line down the middle of the spotting tile. Write the numbers and the letters C and H on the spotting tile, as shown in Fig. 1.1.
1 2 1 2 dimple
3 4 3 4
5 6 5 6
C H
Fig. 1.1
Step 2 Place one drop of iodine solution into each of the labelled dimples on the spotting tile.
Step 3 Label one test-tube C and the other test-tube H. Place the test-tubes in the test-tube rack.
Step 4 Use the syringe to put 2 cm3 of starch suspension into test-tube C and into test-tube H.
Step 5 Place test-tube C and the test-tube labelled amylase C into the water in beaker C.
Start the stop-clock.
Step 6 After three minutes, stop the stop-clock and pour the contents of test-tube amylase C into test-tube C.
Restart the stop-clock, wait for 30 seconds and then continue to step 7.
Step 7 Use a pipette to remove a sample of liquid from test-tube C.
Place two drops of this sample into the dimple labelled C1 on your spotting tile. Return the rest of the sample in the pipette to test-tube C.
Step 8 Observe the colour of the liquid in dimple C1. Record this colour in your table in 1(a)(i).
Step 9 Repeat step 7 and step 8 at 30-second intervals, using the dimples labelled C2, C3, C4,
C5 and C6.
Step 10 Raise your hand when you are ready for hot water to be added to beaker H.
Step 11 Place test-tube H and test-tube amylase H into the hot water in beaker H. Reset the stop-clock to zero. Start the stop-clock again.
Step 12 After three minutes, stop the stop-clock and pour the contents of test-tube amylase H into test-tube H. Restart the stop-clock, wait for 30 seconds and then continue to step 13.
Step 13 Use a pipette to remove a sample of the liquid from test-tube H.
Place two drops of this sample into the dimple labelled H1 on your spotting tile. Return the rest of the sample in the pipette to test-tube H.
Step 14 Observe the colour of the liquid in dimple H1. Record this colour in your table in
1(a)(i).
Step 15 Repeat step 13 and step 14 at 30-second intervals, using the dimples labelled H2, H3,
H4, H5 and H6.
(a) (i) Prepare a table for your results.
[4]
(ii) State the colour of iodine solution when starch is present.
…… [1]
(iii) State a conclusion for your results.
…… [1]
(iv) State the independent variable in this investigation.
…… [1]
(v) State two variables that were kept constant in this investigation.
1 ……
2 ……
[2]
(b) (i) Explain why the method used in this investigation does not allow you to obtain an accurate time for the breakdown of starch.
…… [1]
(ii) The temperature of the water in the beakers during the investigation was a source of error.
Describe how you could improve the method to reduce this error.
…… [1]
[Total: 11]
Mark scheme
1(a)(i) table drawn with minimum three columns and a header line 4
appropriate column / row headings ;
recording of, 12 colours / results ;
correct trend ; ‘yellow-brown’ or equivalent negative result occurs in H
before it occurs in C
1(a)(ii) blue-black ; 1
1(a)(iii) conclusion that matches results ; 1 expected conclusion:
the greater the temperature the greater the,
enzyme / amylase, activity / AW / ora ;
1(a)(iv) temperature ; 1
1(a)(v) any two from: 2
(number of) drops of iodine (solution ;
volume of amylase ;
concentration of amylase ;
same enzyme ;
volume of starch (suspension) ;
time for equilibration / AW ;
sample intervals / time intervals ;
number of drops of sample added to iodine (solution) ;
1(b)(i) any one from: 1
idea that colour change might take place between sampling
times ;
time intervals were too long ;
difficult to judge end point / colour change is subjective / it is
qualitative ;
1(b)(ii) any one from: 1
insulate the beaker / AW ;
use a thermostatically controlled water-bath ;
description of using a Bunsen burner and a thermometer to
control the temperature ;
(a) Milk contains fats. The enzyme lipase catalyses the breakdown of fats to form fatty acids and glycerol. The fatty acids cause the pH of the milk to decrease.
Plan an investigation to determine the effect of lipase concentration on the breakdown of fats in milk.
…… [6]
(b) The emulsion test is used to test a sample of food for fat.
Describe the method you would use to do the emulsion test.
…… [2]
[Total: 8]
Mark scheme
2(a) independent variable: 6
1 (at least) two different, enzyme / lipase, concentrations ;
dependent variable:
2 measuring pH after a set time OR measuring time to
reach a certain pH ;
detail of method:
3 use of pH meter / pH paper / (named) indicator ;
4 measure / same, initial pH / initial colour ;
5 control and description of the control e.g. using boiled
enzyme / water instead of enzyme ;
6 & 7 variables kept constant – max two from ;;
• volume of milk
• type of milk / same milk / fat content of milk
• volume of, lipase / enzyme
• temperature
• volume of indicator
8 two or more repeats / total of three or more trials ;
9 relevant safety precaution e.g. use of goggles / gloves ;
2(b) add ethanol and (then) water ; 2
shake ;
Fig. 3.1 is a photograph of a type of seaweed called bladder wrack. The bladders help the seaweed float in water.
P bladder
Q
Fig. 3.1
(a) (i) Draw a large diagram of the bladder wrack seaweed shown in Fig. 3.1.
[4]
(ii) Line PQ on Fig. 3.1 represents the length of one bladder on the bladder wrack seaweed.
The actual length of the bladder is 19 mm.
Measure the length of line PQ on Fig. 3.1.
length of line PQ …… mm
Calculate the magnification of the photograph using the formula and your measurement.
length of line PQ magnification = actual length of the bladder
Give your answer to two decimal places.
Space for working.
[3]
(iii) Seaweeds are species of algae that live in the sea. Fig. 3.2 shows photographs of bladder wrack seaweed and a different species of seaweed called egg wrack. The photographs are the same magnification.
bladder wrack egg wrack
Fig. 3.2
State two ways, visible in Fig. 3.2, that bladder wrack is different from egg wrack.
1 ……
2 ……
[2]
(b) Bladder wrack is found on the seashore and is exposed to the air when it is not covered by water at certain times of day.
Students investigated how rapidly bladder wrack lost water. They used this method:
• Three samples of bladder wrack were collected.
• The samples were blotted with tissue to remove any water on the surface of the seaweed.
• The initial mass of each sample was recorded.
• The samples were hung from a piece of string stretched between two stands.
• The mass of each sample was recorded every 30 minutes for the first two hours and then every hour for a further three hours.
(i) Suggest two variables that the students should keep constant during their investigation to ensure that the results are valid.
1 ……
2 ……
[2]
Table 3.1 shows the initial masses recorded by the students and the final masses recorded after five hours.
Table 3.1
initial mass of final mass of sample bladder wrack / g bladder wrack / g
1 178 82
2 184 144
3 167 70 mean 176 76
(ii) One of the final masses recorded is anomalous.
State what is meant by an anomalous result.
…… [1]
(iii) Describe how the students calculated the mean value for the final mass of the bladder wrack.
…… [1]
(iv) Using the information in Table 3.1, calculate the mean percentage decrease in the mass of the bladder wrack samples after five hours.
Give your answer to two significant figures.
Space for working.
…… %
[2]
(c) The students repeated their investigation using egg wrack seaweed.
Table 3.2 shows the mean percentage decrease in the mass of the egg wrack samples throughout the investigation.
Table 3.2
mean percentage decrease in the time / minutes mass of the egg wrack
30 0
60 13
90 22
120 27
180 38
240 46
300 51
Using the data in Table 3.2, plot a line graph on the grid to show the effect of time on the mean percentage decrease in the mass of the egg wrack.
[4]
(d) Many people eat seaweed.
State the names of the reagents that can be used to test seaweed for protein and vitamin C.
protein ……
vitamin C ……
[2]
[Total: 21]
Mark scheme
3(a)(i) outline – single clear line no shading ; 4
size – frond length at least 114 mm ;
detail 1: 7 bladders drawn ;
detail 2: central midrib shown as a double line at least up to
the point at which the midrib branches ;
3(a)(ii) line PQ = 12 ± 1 mm ; 3 MP1 correct measurement
0.63 ;; MP2 dividing their measurement by 19, R if incorrect unit
given with the answer
MP3 correct rounding to two decimal places
A 0.58 / 0.68 if measured as 11 or 13 mm
ecf MP2 / MP3 from error in previous step
3(a)(iii) any two from: 2
bladder wrack has more bladders ;
bladders are closer together ;
bladder wrack, has bladders in pairs / either side of mid rib,
or egg wrack has single bladders ;
bladder wrack has a central mid rib ;
bladder wrack, divides into two at the end / more branched ;
bladder wrack is, wider / thicker / AW, (all the way along) ;
bladder wrack is, lighter / brighter, (in colour) ;
bladder wrack (fronds) are all in the same direction ;
bladder wrack has smaller bladders ;
bladder wrack has rounded ends / smoother ;
AVP ;
3(b)(i) any two from: 2
temperature ;
wind (speed) ;
humidity ;
species / type, of seaweed ;
age of seaweed ;
size / length / surface area ;
idea of how long the bladder wrack has been out of the
water ;
measuring time / interval time (between measuring mass) /
sampling times ;
spacing while hung up ;
amount of blotting / blotting time / blotting method / type of
blotting paper ;
3(b)(ii) a result that does not fit the pattern / trend / AW ; 1
3(b)(iii) did not include sample 2 in the calculation / AW ; 1
3(b)(iv) 57 (%) ;; 2 MP1 correct calculation
MP2 correct rounding to two significant figures
ecf MP2 from incorrect MP1
3(c) axes labelled with units ; 4
suitable size with a linear scale and data that occupies at
least half of the grid in both directions ;
all seven points plotted accurately ± half a small square ;
suitable line drawn ;
3(d) biuret ; 2
DCPIP ;
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On this page, free: the mark scheme for IGCSE Biology 0610/52, October/November 2023 (0610_w23_ms_52), and the question paper (0610_w23_qp_52), to read or download, with each question's marking points written out underneath.
How many marks is 0610/52 out of?+
Biology 0610/52 for October/November 2023 is out of 40 marks, with 1 hour 15 minutes to answer it, across 3 questions.
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